Straight cut leaves a ridge/lip?

[RobynPlater]

Hi Everyone,

The following is happening when I'm straight cutting mount board to size.

IMG_1597.jpg (355.28 KiB) Viewed 4276 times

When I'm cutting mountboard to size by straight cutting it is leaving a ridge/lip on the underside. Initially I thought I had a dull blade, so changed it to a brand new one but it hasn't rectified the problem.

Equipment:
Ultimat Gold mountcutter
Utility blade type 1992 60mm
Mountboard used in the attached photo Arqadia Blackcore 1400 MICS (but does it on each type of board I used).

Any suggestions or ideas about what I'm doing wrong would be very much appreciated.

Thanks
Robyn

[stcstc]

you using a slip mat?

also are they going in frames, if so, does the lip really matter?

[Roboframer]

You're using the wrong blade - http://www.lionpic.co.uk/product/UTILIT ... ,1310.aspx it's too long, too thick - (not sure how that would cause that effect though) and not recommended like this one is http://www.lionpic.co.uk/product/UTILIT ... ,1310.aspx it's double honed - maybe that makes a difference?

I tried that longer/thicker blade in my Ultimat Gold and there was a problem, not your problem, but something else I can't remember - will see tomorrow.

You shouldn't need a slip mat.

[Jonny2morsos]

Thicker blades do cause this to happen. I am sure Keencut will advise if you give them a call. Their technical backup is secone to none.

[Roboframer]

Interesting that under 'knives & blades' on Lion's website, there are no Keencut blades, to find those you have to search for 'Keencut'.

Here's the keencut blades and there isn't one that matches the length/thickness of the one in the OP here. http://www.lionpic.co.uk/product-search ... &c=1232&t=

The one that matches the smaller un-branded version is £23.32 per 100 compared to £8.95 for the un-branded. Out of the two un-branded blades (in my links above) the larger one (the one used in the OP) is cheaper than the smaller one.

Buy the smaller one - real McCoy or unbranded - and I think your problem will disappear.

[Jonny2morsos]

Also blackcore mount board is very dense so the problem will be accentuated.

I noticed yesterday when cutting some mounts from a new batch of Arqadia whitecore board that it seemed much denser than normal. Even with a new blade it took a lot more effort to cut.

[Roboframer]

Here's the problem I had with the longer blade.

blade 25.jpg

Unless you poke the blade too far out, (which there is no advantage in, it just makes for more resistance when you cut) the other end is left poking out and is dangerous.

[Not your average framer]

The 1992 blade is not only longer than the normal 1991 blade, but it is also a thicker blade as well.

The normal 1991 blade is 17 thou thick, but the "heavy duty" 1992 blade is 25 thou thick.

I've not tried using the 1992 blade in a Keencut ultimat, but I have used it in my Keencut System 4000 and the normal 1991 blade does produce a much cleaner cut.

I think you need to try the thinner blades instead.

I hope this helps.

[RobynPlater]

Thanks for all your tips. I've gone away and done some more experimenting and have found out the following:

1. Yep - I am using the wrong type of blade and yes, I had the situation with the tip sticking out the back as illustrated by Roboframer (sore thumb also proves that it is dangerous too!). Beginners' error.
2. I hadn't used a slip mat, but have tried it with one and have found that it did improve the cut (even when still using the incorrect blade). Will try it without a slip mat when correct blades arrive.

Thanks again for all your advice. As someone who is very new to framing (if you hadn' t picked that up already) all this help from experienced framers is invaluable.